The yellow shaded area
represents the range of monthly mean values that have occurred from 1985 to 2014. The blue line shows the monthly mean values for each month
over that same time period. The red line shows what the current years
conditions are and how they compare to the range and the average values
we've seen.

*Note that the Mean pH is now correctly calculated by converting pH values to the representative H+ ion concentrations, averaging those concentrations, and converting back to pH scale. Prior to 2012, we were displaying averages of pH readings, which was statistically incorrect since pH readings are on a logarithmic scale.

NOTE:
Results displayed are provisional and have not undergone full Quality
Assurance procedures. Although Maryland DNR believes the data presented
here are correct, we cannot guarantee their accuracy at this time.